The present disclosure relates generally to turbine engines, and particularly to turbine engine fuel delivery.
With increasing demands for natural gas, there is increased interest in the use of low heating value (LHV) fuels, including syngas and waste process gasses, such as blast furnace gasses produced as a byproduct of steel making that include remaining energy or flammability, for example. Typically, such remaining energy within waste process gasses is burnt off to reduce a likelihood of concentration and flammability concerns. Recovery and utilization of the remaining energy within waste process gasses includes use as a fuel for gas turbine engines, which may then provide electrical or mechanical power.
Such waste process gasses typically contain about one-tenth the thermal energy (such as British thermal units (BTU's) for example) of typical high heating value (HHV) gasses, such as natural gas for example. Therefore a greater ratio of fuel to air is required when operating a turbine on LHV waste process gas. Typical approaches to the large flows of LHV fuel that result from increased fuel to air ratios include injection of air accompanying the LHV gas into a liner of a combustion chamber of the turbine where the fuel and air are mixed before ignition.
The large flows of LHV gasses and their reduced thermal energy gasses can result in ineffective mixing of fuel and air, which thereby provides reduced combustion flame stability and a probability that the flame will blow out, resulting in an interruption of energy provided by the turbine. One approach to avoid such flame blowouts and service interruptions is a combination of HHV gasses with the LHV gasses to sustain turbine operation. However, because of availability and cost concerns, it is generally desired to reduce consumption of such HHV gasses. Accordingly, there is a need in the art for a turbine engine fuel delivery arrangement that overcomes these drawbacks.